For my clients that need hosting services I set up individual accounts under my own name. Usually I include web hosting in my fees. Occasionally I have invoiced a client for the fees. When my contract ends with the client, I contact the hosting company and fill out the paperwork to transfer the account to the client.
The other reason I do it is that I am also a reseller and receive a commission for all of the accounts I bring in to my web host (
Lunarpages). I do allow clients to choose another host or set up their own hosting, but Lunarpages has been solid for me for over 5 years. I also inform clients that I am a reseller of hosting services.
If you tack those new accounts onto your current account it might get messy if you end up trying to transfer the account. You can always contact your web host and see what they suggest.
Also, everyone that handles web hosting for clients (and does not have a private server) should become a reseller. Depending upon your web host, it can provide decent annual income.